问题
Does rax get offset plus the address of this instruction, or the next? From a microcode point of view it might be easier if the answer was the next instruction.
回答1:
The next. That's a general rule on x86 (see also branches).
In Intel's manual volume 2 section 2.2.1.6 RIP-Relative Addressing:
A new addressing form, RIP-relative (relative instruction-pointer) addressing, is implemented in 64-bit mode. An effective address is formed by adding displacement to the 64-bit RIP of the next instruction.
回答2:
Note that symbol_name(%rip) calculates the offset required to reach symbol_name from here, rather than adding the absolute address of symbol_name to RIP as an offset.
But yes, for numeric offsets like mov 4(%rip), %rax, that will load 8 bytes starting at 4 bytes past the end of this instruction.
来源：https://stackoverflow.com/questions/29421766/what-does-mov-offsetrip-rax-do